1. Field of the Invention
The invention relates to a stacked structure for an image sensor, and more particularly to a stacked structure in which a photosensitive chip and integrated circuits with different functions may be integrally packaged.
2. Description of the Related Art
A general sensor is used for sensing signals that may be image signals or audio signals. The sensor of the invention is used to receive image (optical) signals and convert the image signals into electrical signals that are to be transmitted to the printed circuit board.
The image sensor is further electrically connected to other packaged integrated circuits in order to possess various functions. For example, the image sensor may be electrically connected to a digital signal processor which is used to process the signals generated by the image sensor. Furthermore, the image sensor may be electrically connected to a micro controller or a central processing unit to possess various functions.
However, a conventional image sensor is individually packaged. Thus, various integrated circuits mating with the image sensor have to be individually packaged with the image sensor. The packaged image sensor and various signal processing units are then electrically connected to the printed circuit board via a plurality of wires. In this structure, a substrate and a package body have to be used when each of the signal processing units and the image sensor are individually packaged, thereby increasing the manufacturing costs. Furthermore, when each of the signal processing units is mounted to the printed circuit board, the required area of the printed circuit board is relatively large. Thus, the products cannot be made thin, small, and light.
Referring to FIG. 1, a conventional stacked structure for an image sensor includes a substrate 10 having a first surface 12 and a second surface 14. Signal input terminals 15 are formed on the first surface 12, and signal output terminals 16, which are to be electrically connected to a printed circuit board 17, are formed on the second surface 14. The image sensor also includes a frame layer 18, a photosensitive chip 26, a plurality of wires 28, a transparent layer 34, and an integrated circuit 19. The frame layer 18 has an upper surface 20 and a lower surface 22, which is adhered to the first surface 12 of the substrate 10 to form a cavity 24 together with the substrate 10. The photosensitive chip 26 is placed within the cavity 24 formed by the substrate 10 and the frame layer 18, and is mounted to the first surface 12 of the substrate 10. Each of the wires 28 has a first terminal 30 electrically connected to the photosensitive chip 26, and a second terminal 32 electrically connected to a corresponding signal input terminal 15 of the substrate 10. The transparent layer 34 is placed on the upper surface 20 of the frame layer 18. The integrated circuit 19 is mounted to the second surface 14 of the substrate 10.
According to the above-mentioned structure, the overall volume of the image sensor is large, and the image sensor cannot be miniaturized.
It is therefore an object of the invention to provide a stacked structure for an image sensor, in which the number of package members may be decreased and the package cost may be lowered.
Another object of the invention is to provide a stacked structure for an image sensor, which is capable of simplifying and facilitating the manufacturing processes.
Still another object of the invention is to provide a stacked structure for an image sensor, in which the area of the image sensor may be reduced.
Yet still another object of the invention is to provide a stacked structure for an image sensor, which can be miniaturized and made more practical in use.
To achieve the above-mentioned objects, the invention provides an image sensor, which is to be electrically connected to a printed circuit board. The image sensor includes a transparent glass layer on which a plurality of signal input terminals and signal output terminals are formed, a photosensitive chip on which a plurality of bonding pads is formed, a substrate, and an integrated circuit. Each of the bonding pads is formed with a projection, and the photosensitive chip is electrically connected to the signal input terminals on the transparent glass layer through the projections. The substrate has a first surface, a second surface, and a first through hole penetrating through the substrate from the first surface to the second surface. The signal output terminals of the transparent glass layer are electrically connected to the first surface of the substrate with the photosensitive chip positioned within the first through hole of the substrate. The second surface is electrically connected to the printed circuit board. The integrated circuit is electrically connected to the second surface of the substrate.
According to above-mentioned structure, the above-mentioned objects can be achieved.